/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming.resources;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NameAlreadyBoundException;
import javax.naming.NameNotFoundException;
import javax.naming.NameParser;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.NotContextException;
import javax.naming.OperationNotSupportedException;
import javax.naming.directory.AttributeModificationException;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.InvalidAttributesException;
import javax.naming.directory.InvalidSearchControlsException;
import javax.naming.directory.InvalidSearchFilterException;
import javax.naming.directory.ModificationItem;
import javax.naming.directory.SearchControls;

import org.apache.naming.StringManager;

/**
 * Proxy Directory Context implementation.
 * 
 * @author Remy Maucherat
 * @version $Revision: 467222 $ $Date: 2006-10-24 11:17:11 +0800 (星期二, 24 十月
 *          2006) $
 */

public class ProxyDirContext implements DirContext {

	// -------------------------------------------------------------- Constants

	public static final String CONTEXT = "context";
	public static final String HOST = "host";

	// ----------------------------------------------------------- Constructors

	/**
	 * Builds a proxy directory context using the given environment.
	 */
	public ProxyDirContext(Hashtable env, DirContext dirContext) {
		this.env = env;
		this.dirContext = dirContext;
		if (dirContext instanceof BaseDirContext) {
			// Initialize parameters based on the associated dir context, like
			// the caching policy.
			BaseDirContext baseDirContext = (BaseDirContext) dirContext;
			if (baseDirContext.isCached()) {
				try {
					cache = (ResourceCache) Class.forName(cacheClassName)
							.newInstance();
				} catch (Exception e) {
					// FIXME
					e.printStackTrace();
				}
				cache.setCacheMaxSize(baseDirContext.getCacheMaxSize());
				cacheTTL = baseDirContext.getCacheTTL();
				cacheObjectMaxSize = baseDirContext.getCacheMaxSize() / 20;
			}
		}
		hostName = (String) env.get(HOST);
		contextName = (String) env.get(CONTEXT);
	}

	/**
	 * Builds a clone of this proxy dir context, wrapping the given directory
	 * context, and sharing the same cache.
	 */
	// TODO: Refactor using the proxy field
	/*
	 * protected ProxyDirContext(ProxyDirContext proxyDirContext, DirContext
	 * dirContext, String vPath) { this.env = proxyDirContext.env;
	 * this.dirContext = dirContext; this.vPath = vPath; this.cache =
	 * proxyDirContext.cache; this.cacheMaxSize = proxyDirContext.cacheMaxSize;
	 * this.cacheSize = proxyDirContext.cacheSize; this.cacheTTL =
	 * proxyDirContext.cacheTTL; this.cacheObjectMaxSize =
	 * proxyDirContext.cacheObjectMaxSize; this.notFoundCache =
	 * proxyDirContext.notFoundCache; this.hostName = proxyDirContext.hostName;
	 * this.contextName = proxyDirContext.contextName; }
	 */

	// ----------------------------------------------------- Instance Variables

	/**
	 * Proxy DirContext (either this or the real proxy).
	 */
	protected ProxyDirContext proxy = this;

	/**
	 * Environment.
	 */
	protected Hashtable env;

	/**
	 * The string manager for this package.
	 */
	protected StringManager sm = StringManager.getManager(Constants.Package);

	/**
	 * Associated DirContext.
	 */
	protected DirContext dirContext;

	/**
	 * Virtual path.
	 */
	protected String vPath = null;

	/**
	 * Host name.
	 */
	protected String hostName;

	/**
	 * Context name.
	 */
	protected String contextName;

	/**
	 * Cache class.
	 */
	protected String cacheClassName = "org.apache.naming.resources.ResourceCache";

	/**
	 * Cache.
	 */
	protected ResourceCache cache = null;

	/**
	 * Cache TTL.
	 */
	protected int cacheTTL = 5000; // 5s

	/**
	 * Max size of resources which will have their content cached.
	 */
	protected int cacheObjectMaxSize = 512; // 512 KB

	/**
	 * Immutable name not found exception.
	 */
	protected NameNotFoundException notFoundException = new ImmutableNameNotFoundException();

	/**
	 * Non cacheable resources.
	 */
	protected String[] nonCacheable = { "/WEB-INF/lib/", "/WEB-INF/classes/" };

	// --------------------------------------------------------- Public Methods

	/**
	 * Get the cache used for this context.
	 */
	public ResourceCache getCache() {
		return cache;
	}

	/**
	 * Return the actual directory context we are wrapping.
	 */
	public DirContext getDirContext() {
		return this.dirContext;
	}

	/**
	 * Return the document root for this component.
	 */
	public String getDocBase() {
		if (dirContext instanceof BaseDirContext)
			return ((BaseDirContext) dirContext).getDocBase();
		else
			return "";
	}

	/**
	 * Return the host name.
	 */
	public String getHostName() {
		return this.hostName;
	}

	/**
	 * Return the context name.
	 */
	public String getContextName() {
		return this.contextName;
	}

	// -------------------------------------------------------- Context Methods

	/**
	 * Retrieves the named object. If name is empty, returns a new instance of
	 * this context (which represents the same naming context as this context,
	 * but its environment may be modified independently and it may be accessed
	 * concurrently).
	 * 
	 * @param name
	 *            the name of the object to look up
	 * @return the object bound to name
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object lookup(Name name) throws NamingException {
		CacheEntry entry = cacheLookup(name.toString());
		if (entry != null) {
			if (!entry.exists) {
				throw notFoundException;
			}
			if (entry.resource != null) {
				// Check content caching.
				return entry.resource;
			} else {
				return entry.context;
			}
		}
		Object object = dirContext.lookup(parseName(name));
		if (object instanceof InputStream)
			return new Resource((InputStream) object);
		else
			return object;
	}

	/**
	 * Retrieves the named object.
	 * 
	 * @param name
	 *            the name of the object to look up
	 * @return the object bound to name
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object lookup(String name) throws NamingException {
		CacheEntry entry = cacheLookup(name);
		if (entry != null) {
			if (!entry.exists) {
				throw notFoundException;
			}
			if (entry.resource != null) {
				return entry.resource;
			} else {
				return entry.context;
			}
		}
		Object object = dirContext.lookup(parseName(name));
		if (object instanceof InputStream) {
			return new Resource((InputStream) object);
		} else if (object instanceof DirContext) {
			return object;
		} else if (object instanceof Resource) {
			return object;
		} else {
			return new Resource(new ByteArrayInputStream(object.toString()
					.getBytes()));
		}
	}

	/**
	 * Binds a name to an object. All intermediate contexts and the target
	 * context (that named by all but terminal atomic component of the name)
	 * must already exist.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if object did not supply all mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void bind(Name name, Object obj) throws NamingException {
		dirContext.bind(parseName(name), obj);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if object did not supply all mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void bind(String name, Object obj) throws NamingException {
		dirContext.bind(parseName(name), obj);
		cacheUnload(name);
	}

	/**
	 * Binds a name to an object, overwriting any existing binding. All
	 * intermediate contexts and the target context (that named by all but
	 * terminal atomic component of the name) must already exist.
	 * <p>
	 * If the object is a DirContext, any existing attributes associated with
	 * the name are replaced with those of the object. Otherwise, any existing
	 * attributes associated with the name remain unchanged.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @exception InvalidAttributesException
	 *                if object did not supply all mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rebind(Name name, Object obj) throws NamingException {
		dirContext.rebind(parseName(name), obj);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object, overwriting any existing binding.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @exception InvalidAttributesException
	 *                if object did not supply all mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rebind(String name, Object obj) throws NamingException {
		dirContext.rebind(parseName(name), obj);
		cacheUnload(name);
	}

	/**
	 * Unbinds the named object. Removes the terminal atomic name in name from
	 * the target context--that named by all but the terminal atomic part of
	 * name.
	 * <p>
	 * This method is idempotent. It succeeds even if the terminal atomic name
	 * is not bound in the target context, but throws NameNotFoundException if
	 * any of the intermediate contexts do not exist.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @exception NameNotFoundException
	 *                if an intermediate context does not exist
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void unbind(Name name) throws NamingException {
		dirContext.unbind(parseName(name));
		cacheUnload(name.toString());
	}

	/**
	 * Unbinds the named object.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @exception NameNotFoundException
	 *                if an intermediate context does not exist
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void unbind(String name) throws NamingException {
		dirContext.unbind(parseName(name));
		cacheUnload(name);
	}

	/**
	 * Binds a new name to the object bound to an old name, and unbinds the old
	 * name. Both names are relative to this context. Any attributes associated
	 * with the old name become associated with the new name. Intermediate
	 * contexts of the old name are not changed.
	 * 
	 * @param oldName
	 *            the name of the existing binding; may not be empty
	 * @param newName
	 *            the name of the new binding; may not be empty
	 * @exception NameAlreadyBoundException
	 *                if newName is already bound
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rename(Name oldName, Name newName) throws NamingException {
		dirContext.rename(parseName(oldName), parseName(newName));
		cacheUnload(oldName.toString());
	}

	/**
	 * Binds a new name to the object bound to an old name, and unbinds the old
	 * name.
	 * 
	 * @param oldName
	 *            the name of the existing binding; may not be empty
	 * @param newName
	 *            the name of the new binding; may not be empty
	 * @exception NameAlreadyBoundException
	 *                if newName is already bound
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rename(String oldName, String newName) throws NamingException {
		dirContext.rename(parseName(oldName), parseName(newName));
		cacheUnload(oldName);
	}

	/**
	 * Enumerates the names bound in the named context, along with the class
	 * names of objects bound to them. The contents of any subcontexts are not
	 * included.
	 * <p>
	 * If a binding is added to or removed from this context, its effect on an
	 * enumeration previously returned is undefined.
	 * 
	 * @param name
	 *            the name of the context to list
	 * @return an enumeration of the names and class names of the bindings in
	 *         this context. Each element of the enumeration is of type
	 *         NameClassPair.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration list(Name name) throws NamingException {
		return dirContext.list(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the class
	 * names of objects bound to them.
	 * 
	 * @param name
	 *            the name of the context to list
	 * @return an enumeration of the names and class names of the bindings in
	 *         this context. Each element of the enumeration is of type
	 *         NameClassPair.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration list(String name) throws NamingException {
		return dirContext.list(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the objects
	 * bound to them. The contents of any subcontexts are not included.
	 * <p>
	 * If a binding is added to or removed from this context, its effect on an
	 * enumeration previously returned is undefined.
	 * 
	 * @param name
	 *            the name of the context to list
	 * @return an enumeration of the bindings in this context. Each element of
	 *         the enumeration is of type Binding.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration listBindings(Name name) throws NamingException {
		return dirContext.listBindings(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the objects
	 * bound to them.
	 * 
	 * @param name
	 *            the name of the context to list
	 * @return an enumeration of the bindings in this context. Each element of
	 *         the enumeration is of type Binding.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration listBindings(String name) throws NamingException {
		return dirContext.listBindings(parseName(name));
	}

	/**
	 * Destroys the named context and removes it from the namespace. Any
	 * attributes associated with the name are also removed. Intermediate
	 * contexts are not destroyed.
	 * <p>
	 * This method is idempotent. It succeeds even if the terminal atomic name
	 * is not bound in the target context, but throws NameNotFoundException if
	 * any of the intermediate contexts do not exist.
	 * 
	 * In a federated naming system, a context from one naming system may be
	 * bound to a name in another. One can subsequently look up and perform
	 * operations on the foreign context using a composite name. However, an
	 * attempt destroy the context using this composite name will fail with
	 * NotContextException, because the foreign context is not a "subcontext" of
	 * the context in which it is bound. Instead, use unbind() to remove the
	 * binding of the foreign context. Destroying the foreign context requires
	 * that the destroySubcontext() be performed on a context from the foreign
	 * context's "native" naming system.
	 * 
	 * @param name
	 *            the name of the context to be destroyed; may not be empty
	 * @exception NameNotFoundException
	 *                if an intermediate context does not exist
	 * @exception NotContextException
	 *                if the name is bound but does not name a context, or does
	 *                not name a context of the appropriate type
	 */
	public void destroySubcontext(Name name) throws NamingException {
		dirContext.destroySubcontext(parseName(name));
		cacheUnload(name.toString());
	}

	/**
	 * Destroys the named context and removes it from the namespace.
	 * 
	 * @param name
	 *            the name of the context to be destroyed; may not be empty
	 * @exception NameNotFoundException
	 *                if an intermediate context does not exist
	 * @exception NotContextException
	 *                if the name is bound but does not name a context, or does
	 *                not name a context of the appropriate type
	 */
	public void destroySubcontext(String name) throws NamingException {
		dirContext.destroySubcontext(parseName(name));
		cacheUnload(name);
	}

	/**
	 * Creates and binds a new context. Creates a new context with the given
	 * name and binds it in the target context (that named by all but terminal
	 * atomic component of the name). All intermediate contexts and the target
	 * context must already exist.
	 * 
	 * @param name
	 *            the name of the context to create; may not be empty
	 * @return the newly created context
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if creation of the subcontext requires specification of
	 *                mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Context createSubcontext(Name name) throws NamingException {
		Context context = dirContext.createSubcontext(parseName(name));
		cacheUnload(name.toString());
		return context;
	}

	/**
	 * Creates and binds a new context.
	 * 
	 * @param name
	 *            the name of the context to create; may not be empty
	 * @return the newly created context
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if creation of the subcontext requires specification of
	 *                mandatory attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Context createSubcontext(String name) throws NamingException {
		Context context = dirContext.createSubcontext(parseName(name));
		cacheUnload(name);
		return context;
	}

	/**
	 * Retrieves the named object, following links except for the terminal
	 * atomic component of the name. If the object bound to name is not a link,
	 * returns the object itself.
	 * 
	 * @param name
	 *            the name of the object to look up
	 * @return the object bound to name, not following the terminal link (if
	 *         any).
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object lookupLink(Name name) throws NamingException {
		return dirContext.lookupLink(parseName(name));
	}

	/**
	 * Retrieves the named object, following links except for the terminal
	 * atomic component of the name.
	 * 
	 * @param name
	 *            the name of the object to look up
	 * @return the object bound to name, not following the terminal link (if
	 *         any).
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object lookupLink(String name) throws NamingException {
		return dirContext.lookupLink(parseName(name));
	}

	/**
	 * Retrieves the parser associated with the named context. In a federation
	 * of namespaces, different naming systems will parse names differently.
	 * This method allows an application to get a parser for parsing names into
	 * their atomic components using the naming convention of a particular
	 * naming system. Within any single naming system, NameParser objects
	 * returned by this method must be equal (using the equals() test).
	 * 
	 * @param name
	 *            the name of the context from which to get the parser
	 * @return a name parser that can parse compound names into their atomic
	 *         components
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NameParser getNameParser(Name name) throws NamingException {
		return dirContext.getNameParser(parseName(name));
	}

	/**
	 * Retrieves the parser associated with the named context.
	 * 
	 * @param name
	 *            the name of the context from which to get the parser
	 * @return a name parser that can parse compound names into their atomic
	 *         components
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NameParser getNameParser(String name) throws NamingException {
		return dirContext.getNameParser(parseName(name));
	}

	/**
	 * Composes the name of this context with a name relative to this context.
	 * <p>
	 * Given a name (name) relative to this context, and the name (prefix) of
	 * this context relative to one of its ancestors, this method returns the
	 * composition of the two names using the syntax appropriate for the naming
	 * system(s) involved. That is, if name names an object relative to this
	 * context, the result is the name of the same object, but relative to the
	 * ancestor context. None of the names may be null.
	 * 
	 * @param name
	 *            a name relative to this context
	 * @param prefix
	 *            the name of this context relative to one of its ancestors
	 * @return the composition of prefix and name
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Name composeName(Name name, Name prefix) throws NamingException {
		prefix = (Name) prefix.clone();
		return prefix.addAll(name);
	}

	/**
	 * Composes the name of this context with a name relative to this context.
	 * 
	 * @param name
	 *            a name relative to this context
	 * @param prefix
	 *            the name of this context relative to one of its ancestors
	 * @return the composition of prefix and name
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public String composeName(String name, String prefix)
			throws NamingException {
		return prefix + "/" + name;
	}

	/**
	 * Adds a new environment property to the environment of this context. If
	 * the property already exists, its value is overwritten.
	 * 
	 * @param propName
	 *            the name of the environment property to add; may not be null
	 * @param propVal
	 *            the value of the property to add; may not be null
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object addToEnvironment(String propName, Object propVal)
			throws NamingException {
		return dirContext.addToEnvironment(propName, propVal);
	}

	/**
	 * Removes an environment property from the environment of this context.
	 * 
	 * @param propName
	 *            the name of the environment property to remove; may not be
	 *            null
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Object removeFromEnvironment(String propName) throws NamingException {
		return dirContext.removeFromEnvironment(propName);
	}

	/**
	 * Retrieves the environment in effect for this context. See class
	 * description for more details on environment properties. The caller should
	 * not make any changes to the object returned: their effect on the context
	 * is undefined. The environment of this context may be changed using
	 * addToEnvironment() and removeFromEnvironment().
	 * 
	 * @return the environment of this context; never null
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Hashtable getEnvironment() throws NamingException {
		return dirContext.getEnvironment();
	}

	/**
	 * Closes this context. This method releases this context's resources
	 * immediately, instead of waiting for them to be released automatically by
	 * the garbage collector. This method is idempotent: invoking it on a
	 * context that has already been closed has no effect. Invoking any other
	 * method on a closed context is not allowed, and results in undefined
	 * behaviour.
	 * 
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void close() throws NamingException {
		dirContext.close();
	}

	/**
	 * Retrieves the full name of this context within its own namespace.
	 * <p>
	 * Many naming services have a notion of a "full name" for objects in their
	 * respective namespaces. For example, an LDAP entry has a distinguished
	 * name, and a DNS record has a fully qualified name. This method allows the
	 * client application to retrieve this name. The string returned by this
	 * method is not a JNDI composite name and should not be passed directly to
	 * context methods. In naming systems for which the notion of full name does
	 * not make sense, OperationNotSupportedException is thrown.
	 * 
	 * @return this context's name in its own namespace; never null
	 * @exception OperationNotSupportedException
	 *                if the naming system does not have the notion of a full
	 *                name
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public String getNameInNamespace() throws NamingException {
		return dirContext.getNameInNamespace();
	}

	// ----------------------------------------------------- DirContext Methods

	/**
	 * Retrieves all of the attributes associated with a named object.
	 * 
	 * @return the set of attributes associated with name. Returns an empty
	 *         attribute set if name has no attributes; never null.
	 * @param name
	 *            the name of the object from which to retrieve attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Attributes getAttributes(Name name) throws NamingException {
		CacheEntry entry = cacheLookup(name.toString());
		if (entry != null) {
			if (!entry.exists) {
				throw notFoundException;
			}
			return entry.attributes;
		}
		Attributes attributes = dirContext.getAttributes(parseName(name));
		if (!(attributes instanceof ResourceAttributes)) {
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves all of the attributes associated with a named object.
	 * 
	 * @return the set of attributes associated with name
	 * @param name
	 *            the name of the object from which to retrieve attributes
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Attributes getAttributes(String name) throws NamingException {
		CacheEntry entry = cacheLookup(name);
		if (entry != null) {
			if (!entry.exists) {
				throw notFoundException;
			}
			return entry.attributes;
		}
		Attributes attributes = dirContext.getAttributes(parseName(name));
		if (!(attributes instanceof ResourceAttributes)) {
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves selected attributes associated with a named object. See the
	 * class description regarding attribute models, attribute type names, and
	 * operational attributes.
	 * 
	 * @return the requested attributes; never null
	 * @param name
	 *            the name of the object from which to retrieve attributes
	 * @param attrIds
	 *            the identifiers of the attributes to retrieve. null indicates
	 *            that all attributes should be retrieved; an empty array
	 *            indicates that none should be retrieved
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Attributes getAttributes(Name name, String[] attrIds)
			throws NamingException {
		Attributes attributes = dirContext.getAttributes(parseName(name),
				attrIds);
		if (!(attributes instanceof ResourceAttributes)) {
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves selected attributes associated with a named object.
	 * 
	 * @return the requested attributes; never null
	 * @param name
	 *            the name of the object from which to retrieve attributes
	 * @param attrIds
	 *            the identifiers of the attributes to retrieve. null indicates
	 *            that all attributes should be retrieved; an empty array
	 *            indicates that none should be retrieved
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public Attributes getAttributes(String name, String[] attrIds)
			throws NamingException {
		Attributes attributes = dirContext.getAttributes(parseName(name),
				attrIds);
		if (!(attributes instanceof ResourceAttributes)) {
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Modifies the attributes associated with a named object. The order of the
	 * modifications is not specified. Where possible, the modifications are
	 * performed atomically.
	 * 
	 * @param name
	 *            the name of the object whose attributes will be updated
	 * @param mod_op
	 *            the modification operation, one of: ADD_ATTRIBUTE,
	 *            REPLACE_ATTRIBUTE, REMOVE_ATTRIBUTE
	 * @param attrs
	 *            the attributes to be used for the modification; may not be
	 *            null
	 * @exception AttributeModificationException
	 *                if the modification cannot be completed successfully
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void modifyAttributes(Name name, int mod_op, Attributes attrs)
			throws NamingException {
		dirContext.modifyAttributes(parseName(name), mod_op, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Modifies the attributes associated with a named object.
	 * 
	 * @param name
	 *            the name of the object whose attributes will be updated
	 * @param mod_op
	 *            the modification operation, one of: ADD_ATTRIBUTE,
	 *            REPLACE_ATTRIBUTE, REMOVE_ATTRIBUTE
	 * @param attrs
	 *            the attributes to be used for the modification; may not be
	 *            null
	 * @exception AttributeModificationException
	 *                if the modification cannot be completed successfully
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void modifyAttributes(String name, int mod_op, Attributes attrs)
			throws NamingException {
		dirContext.modifyAttributes(parseName(name), mod_op, attrs);
		cacheUnload(name);
	}

	/**
	 * Modifies the attributes associated with a named object using an an
	 * ordered list of modifications. The modifications are performed in the
	 * order specified. Each modification specifies a modification operation
	 * code and an attribute on which to operate. Where possible, the
	 * modifications are performed atomically.
	 * 
	 * @param name
	 *            the name of the object whose attributes will be updated
	 * @param mods
	 *            an ordered sequence of modifications to be performed; may not
	 *            be null
	 * @exception AttributeModificationException
	 *                if the modification cannot be completed successfully
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void modifyAttributes(Name name, ModificationItem[] mods)
			throws NamingException {
		dirContext.modifyAttributes(parseName(name), mods);
		cacheUnload(name.toString());
	}

	/**
	 * Modifies the attributes associated with a named object using an an
	 * ordered list of modifications.
	 * 
	 * @param name
	 *            the name of the object whose attributes will be updated
	 * @param mods
	 *            an ordered sequence of modifications to be performed; may not
	 *            be null
	 * @exception AttributeModificationException
	 *                if the modification cannot be completed successfully
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void modifyAttributes(String name, ModificationItem[] mods)
			throws NamingException {
		dirContext.modifyAttributes(parseName(name), mods);
		cacheUnload(name);
	}

	/**
	 * Binds a name to an object, along with associated attributes. If attrs is
	 * null, the resulting binding will have the attributes associated with obj
	 * if obj is a DirContext, and no attributes otherwise. If attrs is
	 * non-null, the resulting binding will have attrs as its attributes; any
	 * attributes associated with obj are ignored.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @param attrs
	 *            the attributes to associate with the binding
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if some "mandatory" attributes of the binding are not
	 *                supplied
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void bind(Name name, Object obj, Attributes attrs)
			throws NamingException {
		dirContext.bind(parseName(name), obj, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object, along with associated attributes.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @param attrs
	 *            the attributes to associate with the binding
	 * @exception NameAlreadyBoundException
	 *                if name is already bound
	 * @exception InvalidAttributesException
	 *                if some "mandatory" attributes of the binding are not
	 *                supplied
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void bind(String name, Object obj, Attributes attrs)
			throws NamingException {
		dirContext.bind(parseName(name), obj, attrs);
		cacheUnload(name);
	}

	/**
	 * Binds a name to an object, along with associated attributes, overwriting
	 * any existing binding. If attrs is null and obj is a DirContext, the
	 * attributes from obj are used. If attrs is null and obj is not a
	 * DirContext, any existing attributes associated with the object already
	 * bound in the directory remain unchanged. If attrs is non-null, any
	 * existing attributes associated with the object already bound in the
	 * directory are removed and attrs is associated with the named object. If
	 * obj is a DirContext and attrs is non-null, the attributes of obj are
	 * ignored.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @param attrs
	 *            the attributes to associate with the binding
	 * @exception InvalidAttributesException
	 *                if some "mandatory" attributes of the binding are not
	 *                supplied
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rebind(Name name, Object obj, Attributes attrs)
			throws NamingException {
		dirContext.rebind(parseName(name), obj, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object, along with associated attributes, overwriting
	 * any existing binding.
	 * 
	 * @param name
	 *            the name to bind; may not be empty
	 * @param obj
	 *            the object to bind; possibly null
	 * @param attrs
	 *            the attributes to associate with the binding
	 * @exception InvalidAttributesException
	 *                if some "mandatory" attributes of the binding are not
	 *                supplied
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public void rebind(String name, Object obj, Attributes attrs)
			throws NamingException {
		dirContext.rebind(parseName(name), obj, attrs);
		cacheUnload(name);
	}

	/**
	 * Creates and binds a new context, along with associated attributes. This
	 * method creates a new subcontext with the given name, binds it in the
	 * target context (that named by all but terminal atomic component of the
	 * name), and associates the supplied attributes with the newly created
	 * object. All intermediate and target contexts must already exist. If attrs
	 * is null, this method is equivalent to Context.createSubcontext().
	 * 
	 * @param name
	 *            the name of the context to create; may not be empty
	 * @param attrs
	 *            the attributes to associate with the newly created context
	 * @return the newly created context
	 * @exception NameAlreadyBoundException
	 *                if the name is already bound
	 * @exception InvalidAttributesException
	 *                if attrs does not contain all the mandatory attributes
	 *                required for creation
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext createSubcontext(Name name, Attributes attrs)
			throws NamingException {
		DirContext context = dirContext
				.createSubcontext(parseName(name), attrs);
		cacheUnload(name.toString());
		return context;
	}

	/**
	 * Creates and binds a new context, along with associated attributes.
	 * 
	 * @param name
	 *            the name of the context to create; may not be empty
	 * @param attrs
	 *            the attributes to associate with the newly created context
	 * @return the newly created context
	 * @exception NameAlreadyBoundException
	 *                if the name is already bound
	 * @exception InvalidAttributesException
	 *                if attrs does not contain all the mandatory attributes
	 *                required for creation
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext createSubcontext(String name, Attributes attrs)
			throws NamingException {
		DirContext context = dirContext
				.createSubcontext(parseName(name), attrs);
		cacheUnload(name);
		return context;
	}

	/**
	 * Retrieves the schema associated with the named object. The schema
	 * describes rules regarding the structure of the namespace and the
	 * attributes stored within it. The schema specifies what types of objects
	 * can be added to the directory and where they can be added; what mandatory
	 * and optional attributes an object can have. The range of support for
	 * schemas is directory-specific.
	 * 
	 * @param name
	 *            the name of the object whose schema is to be retrieved
	 * @return the schema associated with the context; never null
	 * @exception OperationNotSupportedException
	 *                if schema not supported
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext getSchema(Name name) throws NamingException {
		return dirContext.getSchema(parseName(name));
	}

	/**
	 * Retrieves the schema associated with the named object.
	 * 
	 * @param name
	 *            the name of the object whose schema is to be retrieved
	 * @return the schema associated with the context; never null
	 * @exception OperationNotSupportedException
	 *                if schema not supported
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext getSchema(String name) throws NamingException {
		return dirContext.getSchema(parseName(name));
	}

	/**
	 * Retrieves a context containing the schema objects of the named object's
	 * class definitions.
	 * 
	 * @param name
	 *            the name of the object whose object class definition is to be
	 *            retrieved
	 * @return the DirContext containing the named object's class definitions;
	 *         never null
	 * @exception OperationNotSupportedException
	 *                if schema not supported
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext getSchemaClassDefinition(Name name)
			throws NamingException {
		return dirContext.getSchemaClassDefinition(parseName(name));
	}

	/**
	 * Retrieves a context containing the schema objects of the named object's
	 * class definitions.
	 * 
	 * @param name
	 *            the name of the object whose object class definition is to be
	 *            retrieved
	 * @return the DirContext containing the named object's class definitions;
	 *         never null
	 * @exception OperationNotSupportedException
	 *                if schema not supported
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public DirContext getSchemaClassDefinition(String name)
			throws NamingException {
		return dirContext.getSchemaClassDefinition(parseName(name));
	}

	/**
	 * Searches in a single context for objects that contain a specified set of
	 * attributes, and retrieves selected attributes. The search is performed
	 * using the default SearchControls settings.
	 * 
	 * @param name
	 *            the name of the context to search
	 * @param matchingAttributes
	 *            the attributes to search for. If empty or null, all objects in
	 *            the target context are returned.
	 * @param attributesToReturn
	 *            the attributes to return. null indicates that all attributes
	 *            are to be returned; an empty array indicates that none are to
	 *            be returned.
	 * @return a non-null enumeration of SearchResult objects. Each SearchResult
	 *         contains the attributes identified by attributesToReturn and the
	 *         name of the corresponding object, named relative to the context
	 *         named by name.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, Attributes matchingAttributes,
			String[] attributesToReturn) throws NamingException {
		return dirContext.search(parseName(name), matchingAttributes,
				attributesToReturn);
	}

	/**
	 * Searches in a single context for objects that contain a specified set of
	 * attributes, and retrieves selected attributes.
	 * 
	 * @param name
	 *            the name of the context to search
	 * @param matchingAttributes
	 *            the attributes to search for. If empty or null, all objects in
	 *            the target context are returned.
	 * @param attributesToReturn
	 *            the attributes to return. null indicates that all attributes
	 *            are to be returned; an empty array indicates that none are to
	 *            be returned.
	 * @return a non-null enumeration of SearchResult objects. Each SearchResult
	 *         contains the attributes identified by attributesToReturn and the
	 *         name of the corresponding object, named relative to the context
	 *         named by name.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, Attributes matchingAttributes,
			String[] attributesToReturn) throws NamingException {
		return dirContext.search(parseName(name), matchingAttributes,
				attributesToReturn);
	}

	/**
	 * Searches in a single context for objects that contain a specified set of
	 * attributes. This method returns all the attributes of such objects. It is
	 * equivalent to supplying null as the atributesToReturn parameter to the
	 * method search(Name, Attributes, String[]).
	 * 
	 * @param name
	 *            the name of the context to search
	 * @param matchingAttributes
	 *            the attributes to search for. If empty or null, all objects in
	 *            the target context are returned.
	 * @return a non-null enumeration of SearchResult objects. Each SearchResult
	 *         contains the attributes identified by attributesToReturn and the
	 *         name of the corresponding object, named relative to the context
	 *         named by name.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, Attributes matchingAttributes)
			throws NamingException {
		return dirContext.search(parseName(name), matchingAttributes);
	}

	/**
	 * Searches in a single context for objects that contain a specified set of
	 * attributes.
	 * 
	 * @param name
	 *            the name of the context to search
	 * @param matchingAttributes
	 *            the attributes to search for. If empty or null, all objects in
	 *            the target context are returned.
	 * @return a non-null enumeration of SearchResult objects. Each SearchResult
	 *         contains the attributes identified by attributesToReturn and the
	 *         name of the corresponding object, named relative to the context
	 *         named by name.
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, Attributes matchingAttributes)
			throws NamingException {
		return dirContext.search(parseName(name), matchingAttributes);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the
	 * given search filter. Performs the search as specified by the search
	 * controls.
	 * 
	 * @param name
	 *            the name of the context or object to search
	 * @param filter
	 *            the filter expression to use for the search; may not be null
	 * @param cons
	 *            the search controls that control the search. If null, the
	 *            default search controls are used (equivalent to (new
	 *            SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisfy the
	 *         filter; never null
	 * @exception InvalidSearchFilterException
	 *                if the search filter specified is not supported or
	 *                understood by the underlying directory
	 * @exception InvalidSearchControlsException
	 *                if the search controls contain invalid settings
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, String filter,
			SearchControls cons) throws NamingException {
		return dirContext.search(parseName(name), filter, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the
	 * given search filter. Performs the search as specified by the search
	 * controls.
	 * 
	 * @param name
	 *            the name of the context or object to search
	 * @param filter
	 *            the filter expression to use for the search; may not be null
	 * @param cons
	 *            the search controls that control the search. If null, the
	 *            default search controls are used (equivalent to (new
	 *            SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisfy the
	 *         filter; never null
	 * @exception InvalidSearchFilterException
	 *                if the search filter specified is not supported or
	 *                understood by the underlying directory
	 * @exception InvalidSearchControlsException
	 *                if the search controls contain invalid settings
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, String filter,
			SearchControls cons) throws NamingException {
		return dirContext.search(parseName(name), filter, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the
	 * given search filter. Performs the search as specified by the search
	 * controls.
	 * 
	 * @param name
	 *            the name of the context or object to search
	 * @param filterExpr
	 *            the filter expression to use for the search. The expression
	 *            may contain variables of the form "{i}" where i is a
	 *            nonnegative integer. May not be null.
	 * @param filterArgs
	 *            the array of arguments to substitute for the variables in
	 *            filterExpr. The value of filterArgs[i] will replace each
	 *            occurrence of "{i}". If null, equivalent to an empty array.
	 * @param cons
	 *            the search controls that control the search. If null, the
	 *            default search controls are used (equivalent to (new
	 *            SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisy the
	 *         filter; never null
	 * @exception ArrayIndexOutOfBoundsException
	 *                if filterExpr contains {i} expressions where i is outside
	 *                the bounds of the array filterArgs
	 * @exception InvalidSearchControlsException
	 *                if cons contains invalid settings
	 * @exception InvalidSearchFilterException
	 *                if filterExpr with filterArgs represents an invalid search
	 *                filter
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, String filterExpr,
			Object[] filterArgs, SearchControls cons) throws NamingException {
		return dirContext.search(parseName(name), filterExpr, filterArgs, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the
	 * given search filter. Performs the search as specified by the search
	 * controls.
	 * 
	 * @param name
	 *            the name of the context or object to search
	 * @param filterExpr
	 *            the filter expression to use for the search. The expression
	 *            may contain variables of the form "{i}" where i is a
	 *            nonnegative integer. May not be null.
	 * @param filterArgs
	 *            the array of arguments to substitute for the variables in
	 *            filterExpr. The value of filterArgs[i] will replace each
	 *            occurrence of "{i}". If null, equivalent to an empty array.
	 * @param cons
	 *            the search controls that control the search. If null, the
	 *            default search controls are used (equivalent to (new
	 *            SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisy the
	 *         filter; never null
	 * @exception ArrayIndexOutOfBoundsException
	 *                if filterExpr contains {i} expressions where i is outside
	 *                the bounds of the array filterArgs
	 * @exception InvalidSearchControlsException
	 *                if cons contains invalid settings
	 * @exception InvalidSearchFilterException
	 *                if filterExpr with filterArgs represents an invalid search
	 *                filter
	 * @exception NamingException
	 *                if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, String filterExpr,
			Object[] filterArgs, SearchControls cons) throws NamingException {
		return dirContext.search(parseName(name), filterExpr, filterArgs, cons);
	}

	// --------------------------------------------------------- Public Methods

	/**
	 * Retrieves the named object as a cache entry, without any exception.
	 * 
	 * @param name
	 *            the name of the object to look up
	 * @return the cache entry bound to name
	 */
	public CacheEntry lookupCache(String name) {
		CacheEntry entry = cacheLookup(name);
		if (entry == null) {
			entry = new CacheEntry();
			entry.name = name;
			try {
				Object object = dirContext.lookup(parseName(name));
				if (object instanceof InputStream) {
					entry.resource = new Resource((InputStream) object);
				} else if (object instanceof DirContext) {
					entry.context = (DirContext) object;
				} else if (object instanceof Resource) {
					entry.resource = (Resource) object;
				} else {
					entry.resource = new Resource(new ByteArrayInputStream(
							object.toString().getBytes()));
				}
				Attributes attributes = dirContext
						.getAttributes(parseName(name));
				if (!(attributes instanceof ResourceAttributes)) {
					attributes = new ResourceAttributes(attributes);
				}
				entry.attributes = (ResourceAttributes) attributes;
			} catch (NamingException e) {
				entry.exists = false;
			}
		}
		return entry;
	}

	// ------------------------------------------------------ Protected Methods

	/**
	 * Parses a name.
	 * 
	 * @return the parsed name
	 */
	protected String parseName(String name) throws NamingException {
		return name;
	}

	/**
	 * Parses a name.
	 * 
	 * @return the parsed name
	 */
	protected Name parseName(Name name) throws NamingException {
		return name;
	}

	/**
	 * Lookup in cache.
	 */
	protected CacheEntry cacheLookup(String name) {
		if (cache == null)
			return (null);
		if (name == null)
			name = "";
		for (int i = 0; i < nonCacheable.length; i++) {
			if (name.startsWith(nonCacheable[i])) {
				return (null);
			}
		}
		CacheEntry cacheEntry = cache.lookup(name);
		if (cacheEntry == null) {
			cacheEntry = new CacheEntry();
			cacheEntry.name = name;
			// Load entry
			cacheLoad(cacheEntry);
		} else {
			if (!validate(cacheEntry)) {
				if (!revalidate(cacheEntry)) {
					cacheUnload(cacheEntry.name);
					return (null);
				} else {
					cacheEntry.timestamp = System.currentTimeMillis()
							+ cacheTTL;
				}
			}
			cacheEntry.accessCount++;
		}
		return (cacheEntry);
	}

	/**
	 * Validate entry.
	 */
	protected boolean validate(CacheEntry entry) {
		if (((!entry.exists) || (entry.context != null) || ((entry.resource != null) && (entry.resource
				.getContent() != null)))
				&& (System.currentTimeMillis() < entry.timestamp)) {
			return true;
		}
		return false;
	}

	/**
	 * Revalidate entry.
	 */
	protected boolean revalidate(CacheEntry entry) {
		// Get the attributes at the given path, and check the last
		// modification date
		if (!entry.exists)
			return false;
		if (entry.attributes == null)
			return false;
		long lastModified = entry.attributes.getLastModified();
		long contentLength = entry.attributes.getContentLength();
		if (lastModified <= 0)
			return false;
		try {
			Attributes tempAttributes = dirContext.getAttributes(entry.name);
			ResourceAttributes attributes = null;
			if (!(tempAttributes instanceof ResourceAttributes)) {
				attributes = new ResourceAttributes(tempAttributes);
			} else {
				attributes = (ResourceAttributes) tempAttributes;
			}
			long lastModified2 = attributes.getLastModified();
			long contentLength2 = attributes.getContentLength();
			return (lastModified == lastModified2)
					&& (contentLength == contentLength2);
		} catch (NamingException e) {
			return false;
		}
	}

	/**
	 * Load entry into cache.
	 */
	protected void cacheLoad(CacheEntry entry) {

		String name = entry.name;

		// Retrieve missing info
		boolean exists = true;

		// Retrieving attributes
		if (entry.attributes == null) {
			try {
				Attributes attributes = dirContext.getAttributes(entry.name);
				if (!(attributes instanceof ResourceAttributes)) {
					entry.attributes = new ResourceAttributes(attributes);
				} else {
					entry.attributes = (ResourceAttributes) attributes;
				}
			} catch (NamingException e) {
				exists = false;
			}
		}

		// Retriving object
		if ((exists) && (entry.resource == null) && (entry.context == null)) {
			try {
				Object object = dirContext.lookup(name);
				if (object instanceof InputStream) {
					entry.resource = new Resource((InputStream) object);
				} else if (object instanceof DirContext) {
					entry.context = (DirContext) object;
				} else if (object instanceof Resource) {
					entry.resource = (Resource) object;
				} else {
					entry.resource = new Resource(new ByteArrayInputStream(
							object.toString().getBytes()));
				}
			} catch (NamingException e) {
				exists = false;
			}
		}

		// Load object content
		if ((exists)
				&& (entry.resource != null)
				&& (entry.resource.getContent() == null)
				&& (entry.attributes.getContentLength() >= 0)
				&& (entry.attributes.getContentLength() < (cacheObjectMaxSize * 1024))) {
			int length = (int) entry.attributes.getContentLength();
			// The entry size is 1 + the resource size in KB, if it will be
			// cached
			entry.size += (entry.attributes.getContentLength() / 1024);
			InputStream is = null;
			try {
				is = entry.resource.streamContent();
				int pos = 0;
				byte[] b = new byte[length];
				while (pos < length) {
					int n = is.read(b, pos, length - pos);
					if (n < 0)
						break;
					pos = pos + n;
				}
				entry.resource.setContent(b);
			} catch (IOException e) {
				; // Ignore
			} finally {
				try {
					if (is != null)
						is.close();
				} catch (IOException e) {
					; // Ignore
				}
			}
		}

		// Set existence flag
		entry.exists = exists;

		// Set timestamp
		entry.timestamp = System.currentTimeMillis() + cacheTTL;

		// Add new entry to cache
		synchronized (cache) {
			// Check cache size, and remove elements if too big
			if ((cache.lookup(name) == null) && cache.allocate(entry.size)) {
				cache.load(entry);
			}
		}

	}

	/**
	 * Remove entry from cache.
	 */
	protected boolean cacheUnload(String name) {
		if (cache == null)
			return false;
		synchronized (cache) {
			return cache.unload(name);
		}
	}

}
